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 Posted: Fri 1:20, 17 Dec 2010 Post subject: ed hardy clothing Exhaust valve thermal overload f |
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Exhaust valve thermal overload fatigue failure analysis
Containing even running under severe overload, for example, 10t 5t goods vehicle run have occurred. Overload the engine running remotely, the exhaust valve neck temperature may reach 830 ~ 850 ~ C, which is equivalent to 214N steel exhaust valves at a high temperature long time, up to 259,[link widoczny dla zalogowanych],6 layered organization, so hard and brittle carbide sheet M2. C6 distributed in the greatly increased number of grain boundaries, making the grain boundary as a potential risk of micro-crack initiation at greatly increased, increasing the risk of fatigue failure. As the temperature increases,[link widoczny dla zalogowanych], material rupture strength at high temperature dramatically. According to cooperative units ,21-4N steel at high temperature, persistent experimentation, the temperature was 750 ℃, 8OO ℃ and 850 ℃,[link widoczny dla zalogowanych], test duration are 100h. Mo East and strong: the exhaust valve thermal overload fatigue failure analysis of the performance of its enduring strength decreased from 160MPa to 80MPa, and then dropped to 50MPa. Visible from 750. C to 850. C, due to temperature increases, the intensity of a lasting decline in high-temperature one-third of the original. While the high temperature tensile strength (rb and conditions of the yield 0 \hot exhaust gases to increase output per unit of time, the corrosive substances (diesel exhaust in the O5 and Na2SO4, gasoline engine exhaust PbO) content in the hot exhaust gases increase, so that increased activity of corrosive substances, resulting in corrosion of the exhaust valve damage also increases. gas corrosion and increase crack propagation, which Ruo and the valve by the superposition of alternating stress, in the corrosion of a Pilao stress state, compared with a single mechanical fatigue damage is much more serious. overload valve and valve seat so that the impact force increase and the highest rate of increase alternating stress, and the workpiece temperature increase also increases the valve thermal shock and thermal fatigue failure probability, while making the plastic valve and valve seat to improve their impact and gas emissions between the erosion caused by deformation increased, so that the coaxial line between them and with the degree of deterioration,[link widoczny dla zalogowanych], in addition to affecting the seal between them, leaving the thermal efficiency of decline, exacerbated by the impact of fatigue damage between them. 3 Conclusion 21 ~ 4N steel exhaust valve overload operation is led to changes in their organization and cause its mechanical properties decrease, greatly reducing the high temperature strength of materials, high temperature fatigue strength and endurance strength, and finally a variety of factors in the fatigue fracture occurred. References: [1 ] Internal Combustion Engine Parts Factory in Shijiazhuang. Internal Combustion Engine Parts Valve EM]. Beijing: China Machine Press ,1997.202 - 206. E2] Wang repair. valve failure from external causes of IJ]. engine parts, 2002, (6) :22-25 . The 11th China International Quality Control & Testing Equipment Exhibition organized by the end of the Materials Research Shanghai, Shanghai Huayi Exhibition & Advertising Co., Ltd. and CCPIT Machinery Sub hosted the 11th China International Quality Control and Testing Equipment Exhibition Council (Q.c.China2006) 1-3 in November 2006 at Shanghai Mart a success. The exhibition attracted more than 180 from around the world exhibiting companies and enterprises, including many international famous companies such as GE, Kodak, Olympus, Emerson sound, Leica, Instron, Spike, Lehman and Puri Division race,[link widoczny dla zalogowanych], etc., show the test instruments and equipment display represents the cutting edge of today's quality control The new equipment and new technologies. also held during the show six of nine subjects and technological exchanges, the content exciting, the audience enthusiastically. has been held l1 term Q. CChina exhibition, has become well known within the industry exhibition, with a number of long-term stability of the exhibitors and visitors. the show is both companies have their place, but also the opportunity to understand the peer; can exchange views and learn with their peers, know ourselves, while direct face to face communication with the users as a platform to understand the market demand information . The 12th China International Quality Control and Testing Equipment Exhibition (QCChina2007), will be held 26-28 September 2007 at China International Exhibition Centre (North Third Ring Road, Chaoyang District, No. 6) at. QCChina Exhibition would have been 11 consecutive sessions held in Shanghai next year for the first time in Beijing debut, when the organizers will do all inputs and carefully orchestrated, to show the content richer, more exciting, welcomed the positive industry attention and active participation. For Learn more about the show, please check the website of the Chinese materials and test. at [link widoczny dla zalogowanych]
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